1. Field of the Invention
The present invention relates to a print control apparatus, a print control method, and a computer program. More specifically, the present invention relates to a technique capable of effectively performing a printing operation by reusing rendering completed data.
2. Description of the Related Art
Recent electro-photographic printing apparatuses and inkjet printing apparatuses could operate speedily and output high-quality images.
A business model newly introduced for such advanced printing apparatuses is called “Print On Demand (POD).” Digital printing machines can be used for the POD because these machines can accept an order of a relatively small lot of job, which cannot be accepted by the conventional printing industry that is basically based on a business model using a large-scale printing apparatus.
As a derivative of the POD, a method generally referred to as Variable Data Print (VDP) is usable for the digital printing machines. According to the VDP, the contents to be printed for each printout product can be flexibly changed with reference to information stored in a database.
More specifically, the VDP is preferably used to print direct mails whose contents need to be changed according to customer information. The direct mails, for example, include information of commodities that can be changed according to preference of each customer or numerical values that are variable according to a usage status, for example, expenses for light and fuel.
Therefore, the VDP is widely used in various markets in which direct mails are frequently generated.
The Personalized Print Markup Language (PPML) is a standard format that can be used to describe a print job for the VDP. As one of characteristic features of the PPML, rendering objects that can be reused in rendering processing are described differently from other rendering objects that are used only one time for the rendering processing.
As described above, the VDP enables to flexibly change the contents to be printed for each printout product with reference to information stored in a database.
In this case, an actual print job may contain similar page contents that are commonly usable among a plurality of records. For example, in a catalog of commodities including customized contents for each customer, an ordering page that describes how to purchase commodities is an example of the common pages.
Another method that is generally referred to as “versioning” enables to replace the contents of a specific page according to each client to generate a customized print job. More specifically, according to the “versioning”, the contents to be printed can be replaced on a page-by-page basis (e.g., a page A for a female customer and a page B for a male customer).
The above-described pages containing common contents can be subjected to Raster Image Processing (RIP) to obtain RIP completed data. The obtained RIP completed data can be cached in a memory of a printer or a hard disk drive (HDD). The stored data can be reused to speedily accomplish printing processing.
However, to this end, it is required to check whether the RIP completed data that corresponds to a current processing target page to be subjected to the RIP is already cached.
Hereinafter, it is now assumed that a Page Description Language (PDL) script is subjected to the RIP. The grammar of the PDL enables to describe information indicating a relationship between two or more pages that are mutually common.
In the RIP performed on the PDL script, information indicating each cache completed page is stored in a printer. The information stored in the printer and the PDL script information can be used to promptly determine whether the current processing target page to be subjected to the RIP is already cached.
However, the grammar of the above-described PPML script does not enable to describe information indicating a relationship between two or more pages that are mutually common.
Accordingly, to determine whether the current processing target page to be subjected to the RIP is already cached, it is required to perform matching determination processing to determine whether a script of the current processing target page to be subjected to the RIP matches with a script that corresponds to the page stored in a cache.
However, if the amount of calculations increase for the matching determination processing, the effects obtained by the page cache processing may be reduced greatly.
A technique discussed in Japanese Patent Application Laid-Open No. 10-021018 is a conventional technique that can cache the processing data on the page-by-page basis. The technique discussed in Japanese Patent Application Laid-Open No. 10-021018 divides the PDL data into a plurality of page data and caches the divided page data. Then, each page data is compared with previous data.
Further, according to the technique discussed in Japanese Patent Application Laid-Open No. 10-021018, if the compared data match with each other as a result of the comparison, then the previous RIP completed data is used for the matched page and execution of the RIP is cancelled.
Thus, the technique discussed in Japanese Patent Application Laid-Open No. 10-021018 can reduce the time required to rasterize printing data in an insertion printing to be performed on the page-by-page basis.
A technique discussed in Japanese Patent Application Laid-Open No. 2006-237825 includes extracting reusable data of each object that can be commonly used for a plurality of pages and combining the extracted reusable data to generate form data. Then, the technique discussed in Japanese Patent Application Laid-Open No. 2006-237825 further includes combining the generated form data with data of an object that is not included in the form data, to perform printing.
However, the technique discussed in Japanese Patent Application Laid-Open No. 10-021018 intends to perform the above-described page cache processing for every PDL object. Therefore, it is required to cache all pages included in a print job and perform comparison processing. The number of times of the matching determination tends to increase.
The technique discussed in Japanese Patent Application Laid-Open No. 2006-237825 requires to generate, beforehand, a list of objects in relation to pages on which the objects appear, to quickly find an object that can be commonly used among two or more pages.
Further, to generate the list, the number of times of the matching determination to be performed between the objects tends to increase.
As described above, to cache RIP completed data of a common page in the processing of a job described by the PPML, it is required to perform matching determination processing between a script of the current processing target page to be subjected to the RIP and a script that corresponds to the page stored in the cache.
However, the above-described conventional technique requires the above-described matching determination processing to be constantly performed. Further, the above-described matching determination processing requires a large amount of calculations. Therefore, the effects obtainable by the page-by-page basis cache may be reduced.